A recombinant bispecific single-chain fragment variable specific for HLA class II and Fc alpha RI (CD89) recruits polymorphonuclear neutrophils for efficient lysis of malignant B lymphoid cells.
J Immunol
; 184(3): 1210-7, 2010 Feb 01.
Article
em En
| MEDLINE
| ID: mdl-20042573
ABSTRACT
Bispecific Abs offer new perspectives for cancer immunotherapy. In this study, we describe a recombinant bispecific single-chain fragment variable (bsscFv) directed against Fc alpha RI (CD89) on polymorphonuclear neutrophils (PMNs) or monocytes/macrophages and HLA class II on lymphoma target cells. Fc alpha RI and HLA class II-directed single-chain fragment variable (scFv) fragments were isolated from phage display libraries, established from the hybridomas A77 and F3.3, respectively. The two scFv molecules were connected with a 20 aa flexible linker sequence. After expression in SF21 insect cells and chromatographic purification, the bispecific molecule showed specific binding to both Ags at K(D) values of 148 +/- 42 nM and 113 +/- 25 nM for the anti-Fc alpha RI and anti-HLA class II scFv components in the bsscFv, respectively. In Ab-dependent cytotoxicity assays with PMNs as effectors and a series of lymphoma-derived cell lines (ARH-77, RAJI, REH, NALM-6, RS4;11), the bsscFv was significantly more cytotoxic than the parental murine IgG1 and its chimeric IgG1 derivative. When targeting primary tumor cell isolates from six patients with B cell malignancies, the killing capacity of the (Fc alphaRI x HLA class II) bsscFv compared favorably to conventional HLA class II mAb. Importantly, the cell lines NALM-6 and RS411, as well as two primary tumor cell isolates, were exclusively lysed by the bsscFv. To our knowledge, this is the first report of an Fc alpha RI-directed bsscFv effectively recruiting PMNs for redirected cytotoxicity against human B cell malignancies. Our data show that an (Fc alpha RI x HLA class II) bsscFv is an interesting candidate for further engineering of small, modular immunopharmaceuticals.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas Recombinantes de Fusão
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Região Variável de Imunoglobulina
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Fragmentos de Imunoglobulinas
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Receptores Fc
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Antígenos HLA-D
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Antígenos CD
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Movimento Celular
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Subpopulações de Linfócitos B
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Anticorpos Biespecíficos
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Citotoxicidade Celular Dependente de Anticorpos
Limite:
Animals
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Humans
Idioma:
En
Ano de publicação:
2010
Tipo de documento:
Article